188
FXUS65 KBYZ 130719
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
119 AM MDT SUN SEP 13 2026
KEY MESSAGES
- BELOW AVERAGE TEMPERATURES THROUGH MID WEEK.
- CHANCE OF SHOWERS (MAINLY LIGHT) THROUGH MONDAY. ISOLATED
THUNDERSTORMS POSSIBLE IN SOUTHEAST MONTANA THIS EVENING AND
OVERNIGHT, POSSIBLY STRONG.
- BRISK WEST WINDS MONDAY; GUSTS OVER 50 MPH POSSIBLE FROM BIG
TIMBER TO HARLOWTON.
DISCUSSION
NEXT 7 DAYS (THROUGH SATURDAY)...
SHORT WAVE RIDGING TODAY AHEAD OF AN APPROACHING UPPER LOW OVER
THE PACIFIC NW WILL LEAD TO WARMER AND MAINLY DRY CONDITIONS
ACROSS OUR CWA TODAY. HIGHS WILL RANGE FROM LOWER 70S TO LOWER
80S. THE PATTERN WILL ALSO INDUCE BRISK SOUTHEAST WINDS ACROSS OUR
EASTERN BORDER COUNTIES WITH GUSTS 25 TO 40 MPH BY THE AFTERNOON.
MODELS TRACK THE PACIFIC LOW EASTWARD INTO THE INTER MOUNTAIN
ROCKIES BY EVENING WITH MID LEVEL FLOW BACKING STRONGLY TO THE
SOUTHWEST OVER OUR REGION.
AS THE LOW TRACKS ACROSS THE REGION SUNDAY NIGHT INTO MONDAY, AND
ASSOCIATED COLD FRONT PUSHES THROUGH OUR AREA, WE SHOULD SEE
ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS DEVELOP.
HOWEVER, THE BEST UPPER DYNAMICS ARE PROGGED TO TRACK NORTH OF OUR
CWA LIMITING POTENTIAL RAINFALL. THAT SAID, THERE IS A BRIEF
WINDOW OF DECENT CAPE AND SHEAR IN OUR SOUTHEAST CORNER (CARTER
COUNTY) WHERE CAMS ARE SUGGESTING SOME CONVECTION. INSTABILITY IS
LIMITED, BUT WE COULD SEE A STRONG CELL OR TWO IN THAT AREA TOWARD
MID TO LATE EVENING. SNOW SHOWERS ARE POSSIBLE OVER THE HIGHEST
ELEVATIONS, THOUGH LITTLE IN THE WAY OF ACCUMULATION IS EXPECTED.
BEHIND THE FRONT, MONDAY WILL FEATURE DRY, COOLER AND BREEZY
CONDITIONS. HIGHS WILL BE RANGE FROM 60S WEST TO AROUND 70 EAST.
WIDESPREAD WESTERLY WIND GUSTS OF 30 TO 50 MPH CAN BE EXPECTED,
WITH THE GREATEST WIND GUSTS ALONG THE WESTERN FOOTHILLS.
LOCATIONS FROM BIG TIMBER NORTH TO JUDITH GAP HAVE ROUGHLY A
40-70% CHANCE AT SEEING WIND GUSTS OF 50 MPH OR GREATER. MODELS
SEEMS TO BE FLIP FLOPPING ON THE STRENGTH OF 700 MB WINDS, SO HAVE
HELD OFF ON ANY WIND HIGHLITES AT THIS TIME, BUT WILL CONTINUE TO
MONITOR THE US-191 CORRIDOR (BIG TIMBER TO JUDITH GAP) FOR
MONDAY. AS WINDS DROP AND SKIES CLEAR OUT MONDAY NIGHT, FROST IS
POSSIBLE (20-40% CHANCE) FOR SOME OF THE COLDER VALLEY LOCATIONS.
ENSEMBLES STILL SIGNAL NW TO CYCLONIC FLOW BEHIND THE DEPARTING
UPPER LOW WILL KEEP TEMPS A LITTLE COOLER THAN NORMAL THROUGH
MIDWEEK. OCCASIONAL SHORTWAVES MAY BRING A CHANCE OF LIGHT SHOWERS
TO THE AREA AT TIMES, MOST NOTABLY IN THE THURSDAY/FRIDAY TIME
FRAME ACCORDING TO THE ECMWF. HOWEVER, ENSEMBLES ARE NOT IN
AGREEMENT WITH THIS, SO A GOOD DEAL OF UNCERTAINTY FOR NOW. HIGHS
ARE FORECAST TO RANGE FROM 60S TO LOWER 70S THROUGH WEDNESDAY.
TEMPERATURES IN THE UPPER 60S TO 70S ARE PROGGED FOR THURSDAY AND
FRIDAY. WE MAY SEE LOWS IN THE 30S FOR MONDAY NIGHT/TUESDAY
MORNING WITH A SLIGHT CHANCE OF FROST POSSIBLE IN THE SOUTH
CENTRAL MT FOOTHILLS. OTHERWISE, LOWS WILL BE MAINLY 40S TO LOWER
50S THIS WEEK. BT
AVIATION
UPSLOPE LOW CLOUDS ALONG THE EASTERN SLOPES OF THE
CRAZY AND BEARTOOTH-ABSAROKA MOUNTAINS WILL LINGER EARLY THIS
MORNING. AREAS OF MVFR CEILINGS ARE EXPECTED WEST OF KBIL,
POTENTIALLY IMPACTING KLVM, K6S0 & KHWQ. THIS WILL CONTINUE TO BE
MONITORED. OTHERWISE, VFR WILL PREVAIL ACROSS THE REGION TODAY.
EXPECT E-SE WINDS TO INCREASE WITH GUSTS OF 25-40 KNOTS EAST OF
KBIL, STRONGEST THIS EVENING. A PACIFIC COLD FRONT WILL SHIFT
WINDS TO WESTERLY TONIGHT WITH GUSTS OF 25-35 KNOTS SPREADING WEST
TO EAST. IN ADDITION, EXPECT A BRIEF PERIOD OF SCATTERED SHOWERS
ALONG THE FRONTAL PASSAGE WITH LOCAL MVFR POSSIBLE. A FEW STRONG
THUNDERSTORMS ARE POSSIBLE IN SOUTHEAST MT (EAST OF ROSEBUD
COUNTY) TONIGHT, AND ANY STORMS THAT DEVELOP COULD BE STRONG AND
PRODUCE BRIEF MODERATE TO HEAVY RAIN AND ENHANCED WIND GUSTS.
JKL/TS
PRELIMINARY POINT TEMP/POPS
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 079 050/067 042/071 047/068 045/075 049/075 048/080
0/U 41/N 00/U 00/B 10/U 33/W 11/U
LVM 077 041/064 034/070 039/068 038/074 042/075 042/080
0/N 41/N 00/U 01/U 11/U 33/W 11/U
HDN 083 045/070 038/074 041/071 040/076 043/077 042/081
0/U 51/N 00/U 00/U 01/U 33/W 11/U
MLS 075 051/068 042/069 048/072 044/075 048/076 046/079
0/N 24/W 00/U 10/B 01/U 23/W 32/W
4BQ 077 052/070 042/072 048/075 045/076 048/077 046/080
0/U 23/W 00/U 00/U 12/W 43/W 32/W
BHK 073 048/069 038/069 042/075 041/075 044/077 042/079
0/N 33/W 00/U 21/B 11/U 34/W 31/U
SHR 084 044/070 036/073 041/070 040/074 043/075 041/079
0/U 21/N 00/U 00/U 12/W 33/W 22/W
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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